Bilateral posterior periventricular nodular heterotopia with cerebellar hypoplasia, communicating hydrocephalus and bilateral hippocampal sclerosis. A case report.

Heterotopias are foci of grey matter in abnormal locations in the brain and are secondary to arrest of neuronal migration. Bilateral periventricular nodular heterotopias (BPVNH) are a rare form of heterotopic disorders. Many varieties of BPVNH with various associations have been reported in the literature, the commonest being the classical X-linked variety usually associated with filamin A gene (FLNA) mutations. The relationship of other types of BPVNH to this gene is variable. We report a rare variety of this entity - BPVNH with cerebellar hypoplasia, communicating hydrocephalus and bilateral hippocampal sclerosis. An exostosis arising from the left petrous temporal bone was an added finding in our patient.